Mcleod gauge



Patented Dec. 18, 1934 H elbert Rose,k Wilkinsbpg, Pa n .Westinghouse Electric pany, East llittsburgh Y Pennsylvania Applieatiori vseptembe'rso, m32, serial N .ness-529 '1o claims.

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eentelniiea ehe eemereeeiee "fha Siiieie" ineens aiieprovidedjipfr changing-the volume of the" huid ch elewaeieii efeltpeesere .iseleeeiierie "The epiaretleweeer'dmg te mylihveniion eemvrieefe eeuiem, ehember. preferably eem- PeeedffeI-ie tsanepeeenefeyliederLeech eee-lees having (C .7a-31x eemmweeeting'passegel "emo j municatigpassageiii so {thatl liquid wmp@ s, Y l

the lgai/ige until it, rises The liquidisifmlfc to lever.; Asuitab1e4sca1e;asisfprvdedbehind .fthe capillary Lubes amenable@ the operator @to ,ascertain :the volume of .lathe ,feasempressed in the closed, .capillaryiuba If `desired,:this:Scale :may

videabeteemhg amete around `thev 5o inhe Open @tube atoianyf desired orY `pre41eberiniried 'vacuum chamber .be protected from excess potentials.

" the vapor electric withdrawing the liquid from thel tubes.

' against outside pressure,

be graduated to read the pressure directly in any desired units.

In the modification shown in Fig. 2, the rigid chamber and the compressing diaphragm have been replaced by a collapsible chamber 40 such as a sylphon bellows. Suitable operating mech-vv anism such as the cam 41 is providedfforipressing the liquid from the'chamber 40 into the gauge and suitable resilient mechanism 42 is provided Vfor distending the bellows against the outside pressure. Y When the gauge is used for measuring the noncondensing gases in a mercury'arcrectifier, 'it isV sometimes desirable to provide'insulating means such as the sleeves 45 and washers 46 lon the bolts v4'? securing the end plates 2 and 3 to the vacuum chamber 1 so that the liquid chamber '105 and its operating mechanism is substantially insulated from the potential of the rectifying device. However, when thejdevice is'attachedto arectifler operating at high voltages,

11 may be low enough to`- permit a-glow discharge between the Vopposite end plates 2 and 3.. For this reason I providesuit- :able insulation 50 around fthe chamber v10 and make the operating mechanism. 28 of insulating material so that the operator-will at all times c as mercury can be used in my device,l'.y preferto. use a liquid of less weight such as gallium, butyl phthalate or other suitable liquids having suitable vapor pressure. 1` f The lighter weight liquids are preferred principally because of the increased scale 4readings or deflections which are obtained byA them, and because,for a given1 scalereading, the gas sample will becompressed to a lesserdegree,

Although any suitable liquid, such reducing `or eliminatingthe hazard of condensa# tion of such gases as watervapor. y In the operation of gauges Athecompressing fluid is frequently forced too a suitable check valve 56 toallow the compressing fluid to return'to the liquidchamber. n

' While I have shown anddescribed spccic. embodiments of ymy invention, it is apparent that changes and modificationsjcan without departing from my invention, I desire, limitations shall be imposed as are embodied in the accompanying claims or as maybe neces-V sitated bythe prior art;4

I claim as my'invention: Y

l. A gauge for measuring the pressure of the non-condensing gases in a vapor-electric device comprising `a chamber .adapted forlconn'ection to device, a; second chamber seal-ed against the pressure outside 'the gauge, there being a passagebetween said chambers, a packing stem, secured in said passage, acapillary tube connected to said stem,a secondV tube con- 1 nected to lsaid stem, said second tube opening into -2.A gauge for measuring the pressure of lthe packing stem,

vthe pressure ink the.

vmarred i means for changing thevolume of vsaid chamberv for forcing a.portion ofthe liquid yinto the'par-k allel tubes, and means for restoring .the'volume' high in. theeauee tubes so that a portion spills out into-the vacuum: chamber. ,I providea passage; 55 equipped withr be made therein; thespirit and scope o f therefore, that only such in said passage, a capillary tube connected to said stem, a second tube connected to said stem, said second tube opening into the rst mentioned chamber, a low vapor pressure liquid in said second chamber and means for decreasing or increasing the volume of saidsecond chamber for pressing the liquid into or withdrawing the liquid outof the tubes, and insulating-means between the second chamber and the vapor electric de- VCE;

3. A gauge for low pressure comprising a gas tight chamber communicating with the pressure to be measured, an :upstanding capillary tube in said chamber, 'said capillary tube being closed at the top, a packing stem communicating with the capillary tube,l a tube communicating with said tube extending in substantial parallel relation with said capillary tube and having an opening to the chamber, a second chamber sealed against atmospherasaidchamber communicating with the liquid in said chamber havinga lowvapor pres` sure and means for changing the volume ofsaid chamberffor fforcing a portion. of theliquid intotheparallel tubes.v 4. A gauge torio-w pressure comprisingagas .tight chamber communicating with'the pressure to be measured, an upstanding capillary tube in.

said chamber, said capillary tube being closed-at the top, a packing stem communicating with the capillary tube, a tubecommuncating with vthe tube extending in substantial'. parallel relation with vsaid capillary tube and. to they chamber, a second.

packing stern, said having an opening chambersealed against atmosphere, said chamber communicating withthe packing stem, a liquid in said chamber having a low vapor .pressure and of saidchamber.

5. A pressure gauge comprising a plate adapted for connection tothe vapor electric device, a second plate insulated fromfsaid iirst. vmentioned, plate, a gauge element between said plates, a liquid chamber'lattached to said second plate and incommunication withsaid gauge element,-means for varying the volume of the liquid chamber andan insulating jacket for said insulated plate. if

6. A gauge for measuring 'the noncondensing gases in a vvapor electric device comprisin'glan element for attachment to theA device, a second element Ainsulated, from thev .first mentioned` ele-` ment, a glass tubebetween said elements forming a chamber communicatingwiththe device, a gauge element in said chambenan operating mechanism for said gauge elementand means' for insulating said operating mechanism. rvj

7. Agauge for measuring the nonecondensing" gases in a vapor electric devicecomprising an element for attachment tothe -device, "asecond element insulated Afrom the viirstinc-:ntioned element, a glass tube between said elements form'- ing a chamber communicatingv with the device,

a gauge element in said chamber, a Asealed liquid chamber in communication .with saidv gaugeV elepacking Stem,I a

for a vvapor electric device liquid chamber communicating with said gauge element, mechanism `for forcing liquid from the liquid chamber into the gauge element and an insulated handle for said mechanism.

9. A gauge of the McLeod type comprising a head having a passage for connection to the pressure to be measured, a valve in said head for closing the passage, a chamber secured to said head, a gauge element in said chamber, a liquid chamber communicating with said gauge element, mechanism for chamber into the gauge element and an insulated handle for said mechanism, and an insulating shield about said liquid chamber.

10. A gauge torlow pressure comprising a gas tight chamber communicating with the pressure to be measured, an upstanding capillary tube in forcing liquid from the said chamber, said capillary tube being closed at the top, a packing stem communicating with the capillary tube, a tube communicating `with the.

packing stem, said tube extending in substantial parallel relationv with said capillary tube and having an opening to the chamber, a second chamber sealed against atmosphere, said chamber communicating with the packing stem, a

liquid in said chamberhaving a low Vapor pressure and means for changing the volume of said chamber for forcing a portion of the liquid into the parallel tubes, a second passage between said chambers and a check valve for allowing liquids to flow from the vacuum chamber to the liquid chamber.

HERBERT A. ROSE.- 

